The AOT of that project - folded out to the radiobutton - looks like this:

When we run the form, it looks like this:

The radiobutton is grouped in the "Show fields" group, and has 3 values:

All fields

Field group

User setup

The properties of that radiobutton are:

So, we know that there are 3 items, and that item 1 has the value (Text) "All fields".
But where are the other 2 values?
Actually, they are also there, and here's how to reveal them:

Step 1: Select the Item property

Step 2: Enter the number of the item for which you want to see or set the value

Step 3: Tab out of the Item property

Notice that the Text property still says "All fields" (Item 1), while we have indicated that we want to see Item 2.
This is due to a refresh issue.
The Text doesn't get refreshed when the Item property changes.
We'll have to do the refresh ourselves.

Step 4: Select the Text property

Step 5: Tab out of the Text property

And there you have the value of the second item :)

These values are actually stored in an array.
This is the part of the .XPO file that defines this RadioButton.
See the highlighted part.

Filtering CongfigId lookup
I encountered a situation where I had a form with
- an unbound StringEdit control of ExtendedDataType ItemId
- an unbound StringEdit control of ExtnededDataType ConfigId
The dropdown on the ConfigId seemed to always be filtered in such a way
that it always showed only the ConfigId's for the ItemId in the ItemId field.
After some debugging, I found out that it was because I had a method called itemId on my form.
Apparently, in the ConfigIdLookup form, the executeQuery of the ConfigTable datasource says:void executeQuery()
{
QueryBuildDataSource qbds = this.query().dataSourceTable(tablenum(ConfigTable));
fieldId fieldId;
;
if(!ctrlTabPageConfig.isActivePage())
{
return;
} fieldId = inventDimFormSetup.callerItemFieldId();
if (fieldId)
{
qbds.addDynalink(
fieldnum(ConfigTable,ItemId),
inventDimFormSetup.callerItemIdFormDatasource().cursor(),
fieldId);
}
else
{
qbds.addRange(fieldnum(ConfigTable,ItemId)).value(inventDimFormSetup.callerItemId());
} super();
}